How severe is CVE-2018-4020?

CVE-2018-4020 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-4020 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 49% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-4020?

CVE-2018-4020 affects Netgate Pfsense. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2018-4020?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2018-4020 published?

CVE-2018-4020 was published on 2018-12-03 and last updated on 2026-06-17.

CVE-2018-4020

CVE-2018-4020 is a high-severity vulnerability in Netgate Pfsense with a CVSS 3.x base score of 7.2. Its EPSS exploit-prediction score of 49% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-78.

Key facts

Severity: High (CVSS 3.x base score 7.2)
CVSS v2: 6.5
EPSS exploit prediction: 49% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-78
Affected product: Netgate Pfsense
Published: 2018-12-03
Last modified: 2026-06-17

Description

An exploitable command injection vulnerability exists in the way Netgate pfSense CE 2.4.4-RELEASE processes the parameters of a specific POST request. The attacker can exploit this and gain the ability to execute arbitrary commands on the system. An attacker needs to be able to send authenticated POST requests to the administration web interface. Command injection is possible in the `powerd_ac_mode` POST parameter parameter.

Frequently asked questions

What is CVE-2018-4020?: An exploitable command injection vulnerability exists in the way Netgate pfSense CE 2.4.4-RELEASE processes the parameters of a specific POST request. The attacker can exploit this and gain the ability to execute arbitrary commands on the system. An attacker needs to be able to send authenticated POST requests to the administration web interface. Command injection is possible in the `powerd_ac_mode` POST parameter parameter.
How severe is CVE-2018-4020?: CVE-2018-4020 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-4020 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 49% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-4020?: CVE-2018-4020 affects Netgate Pfsense. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2018-4020?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-4020 published?: CVE-2018-4020 was published on 2018-12-03 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2018-0690

Affected products (1)

cpe:2.3:a:netgate:pfsense:2.4.4:*:*:*:*:*:*:*

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